Problem: Vanessa ate 4 slices of cake. Christopher ate 4 slices. If Vanessa ate $\dfrac{4}{11}$ of the cake, what fraction of the cake is remaining?
Answer: If 4 slices represent $\dfrac{4}{11}$ of the cake, there must have been a total of 11 slices. $\text{fraction of cake remaining} = \dfrac{\text{number of slices remaining}}{\text{number of slices total}}$ Together they ate 8 slices, which leaves 3 out of 11 slices remaining. There is $\dfrac{3}{11}$ of the cake remaining.